This invention pertains to the non-destructive internal and external inspection of produce, including the detection of pits in various stone fruits.
In the area of food processing and production, most stone fruit (peaches, apricots, cherries, prunes, dates and olives) are mechanically pitted. With the mechanical means available today, complete pit removal does not always occur. Often pits or pit fragments remain in the fruit after they have been through the mechanical pitting device and go undetected through the remainder of the processing stage. This could result in damage to equipment or an unwanted pit in the end product resulting in injury or death to persons.
The problem of pit detection has plagued food processors for many years and has resulted in the expenditure of large amounts of money in the replacement of equipment (slicers, dicers, etc.) which have been destroyed due to undetected pits and fragments. With regard to undetected pits in the end product, processors and insurance companies have faced the problem of product liability claims from injuries to the consumer. As a result, the industry has sought accurate and reliable means to detect and reject fruit which still contains pits or pit fragments after the fruit is mechanically pitted. The industry has also sought ways to reject fruit which contains internal damage, has external diseases or blemishes, or which does not meet specific size and shape requirements.
Several types of automated devices have been developed to address certain aspects of these needs. For example, U.S. Pat. No. 3,467,254 issued to Simmons on Sept. 16, 1969, describes an apparatus for detecting pits or remnants in split peaches. U.S. Pat. No. 3,005,549 issued to Flanders et al. on Oct. 24, 1961, describes peach pit fragmentation detection means and techniques for peach halves. Both of these inventions require the fruit to be split in half before inspection, and further require specific orientation of the fruit in the apparatus. These inventions are directed to detecting pits and fragments in large fruits such as peaches, but not in smaller fruits such as cherries or olives or where the processor desires the fruit to remain whole.
U.S. Pat. No. 3,385,434 issued to Nelson on May 28, 1968, describes an apparatus for classifying objects according to their internal structure. The invention uses light beams to view the interior structure of kernels of corn and sort the kernels according to different interior colors, but would not distinguish between a pit in an article of fruit or some other type of variation in internal structure.
An apparatus for detecting seeds in small fruit such as cherries is described in U.S. Pat. No. 3,275,136 issued to Allen et al. on Sept. 27, 1966. In this invention, the pit must be positioned substantially in line with a light source thus, making detection difficult if the pit is off center within the fruit or the fruit is irregularly shaped. Variations in size of the fruit could also make detection difficult.
U.S. Pat. No. 3,768,645 issued to Conway et al. on Oct. 30, 1973, describes a method and apparatus for evaluating articles of produce on the basis of their uniformity and non-uniformity to their transparency to x-rays. U.S. Pat. No. 3,930,994 issued to Conway et al. on Jan. 6, 1976, describes a similar method and apparatus using light rays. In these inventions, the fruit is preoriented which is impractical for high speed evaluation of smaller fruits such as cherries.
U.S. Pat. No. 4,534,470 issued to Mills on Aug. 13, 1985, shows an apparatus and method for processing and sorting fruit as a function of color, blemish, size, shape and other variables by uniformly illuminating the entire surface of the article. The invention does not detect light transmitted through the fruit which would be necessary for detection of pit or internal abnormalities.
U.S. Pat. No. 4,666,045 issued to Gillespie et al. on May 19, 1987, describes a pit detection apparatus and method for detecting the presence of pits or pit fragments in fruit by subjecting the fruit to an optical scanning beam as the fruit passes through an inspection zone. With this invention, the fruit is scanned in only one dimension with a single sweeping scanning beam which could make detection difficult if the pit or pit fragment is not centered in the fruit or attaches to the external surface of the fruit after pitting. In addition, lack of symmetry of shape or discolorations or abnormalities on the surface of the fruit could be mistaken for a pit or cause pits to go undetected. Also, the physical size of the apparatus is impractical for commercial use.
Although the foregoing inventions address some of the various needs of the industry, no single invention is capable of pit detection, and internal and external inspection of an article of produce. These various inventions also have certain sensitivities to size, shape, color, and orientation of the article of produce being inspected. Furthermore, fruit which contains pits which are off-center or pits which remain attached to the surface of the fruit after pitting can pose pit detection errors.